The subject matter disclosed herein relates generally to control systems and, more particularly, to distributed control systems.
Control systems are often used in conjunction with process systems, such as manufacturing or production processes, to regulate and/or monitor various operating parameters of the process. For instance, a control system may regulate the values of certain input parameters of the process in order to drive one or more target output parameters (e.g., flow rate, power output, etc.) to a desired value. Some control systems may also provide process data to an operator in the form of visual feedback, such as by outputting certain selected data points through a human-machine interface (HMI), which may include a graphical user interface displayed using a display device. This may enable the operator to monitor and assess the process performance parameters in substantially real time and, if necessary, take corrective actions if certain parameters are deviating from an expected range or norm.
Certain control systems may be implemented using a distributed control system (DCS) architecture. In a DCS, the control elements may be distributed at various locations throughout the process instead of being arranged at a centralized location. For instance, various control components, such as sensors, actuators, sub-controllers, and so forth, may be distributed throughout the process, but may be networked communication with a main controller of the DCS. In certain DCSs, multiple controllers may be provided for redundancy and safety issues, with only one controller being a designated controller at any given time. For instance, if a current designated controller malfunctions or goes offline, another controller may be selected as the designated controller. In such systems, the designated controller may function as a server providing process data to the HMI, acting as a client. However, some HMI clients that are based on redundant controllers may not be able to detect a change in a designated controller and connect to that designated controller. Thus, an operator may have to manually re-establish a connection between the HMI client and the designated controller, which may be time consuming and inconvenient. Additionally, requiring an operator to manually identify changes in a designated controller and manually reconnect an HMI to the designated controller may result in loss of data or information, which may present potential safety issues.